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Cpm schedules - resource quantities and workloads

Resource quantity and effort units are not the same and must be defined using different units of measure. Resource Quantity might be 1 ea. For the same assignment effort units might be 24 man-hours if labor resource.

The need for separate fields for resource quantity and effort is not just a matter of convenience it is also a matter of getting reliable resource overload visibility and resource leveling.

Cpm schedules - resource quantities and workloads

1.
Resource Quantities:
o Resource quantity and effort units are not the same and
must be defined using different units of measure. Resource
Quantity might be 1 ea. For the same assignment effort
units might be 24 man-hours if labor resource.
o Calculating the required quantity from effort units is not
always easy, a simple conversion factor will not make it.
An average makes sense only when all resources are busy
all the time, otherwise you might under/over estimate the
required quantity.
o Communicating a resource plan by only using effort is not
good enough.
o Most commercially available CPM scheduling software do
not consider resource quantity but only effort units.
Quantities & Workloads 1

2.
Quantities & Workloads 2
There is no simple relationship between resource hours [effort] and
resource quantity. Staggering of activities, multiple activity and
resource calendars on multiple shifts complicate the relationships.
When there are partial workloads it becomes impossible to get
reliable quantities.

3.
Resource Workloads:
o We define workload as the percentage of time a resource
is uniformly distributed throughout team execution.
o If less than 100% we call it partial workload.
o Sharing of some resources on part time basis is an
everyday issue no scheduler or project manager can
overlook.
o Some activities [such as concrete pouring] work only part
of the day sharing their resources the remaining part of
the day with other activities.
o Some resources [such as a crane] work only part of the
day on any given activity and the remaining part of the
day with other activities.
Quantities & Workloads 3

4.
Quantities & Workloads 4
Sharing of equipment such as a crane is an everyday issue in multi-
story building construction .

5.
Quantities & Workloads 5
Scenario:
There are three activities.
There are no links among the activities.
There are two Resource A available.
There are three Resource B available.
Duration of all activities is eight hours.
All activities and resources share the
same 8h/day calendar.
All activities require one Resource A with
60% workload and one Resource B with
100% workload as a single team.
Non-leveled
Schedule
Resource constraints
are about available
resource quantities.

6.
Quantities & Workloads 6
If resources are to work together as a team while multi-tasking it will
take two days.

7.
Quantities & Workloads 7
If resources were allowed to work independent of each other as
separate teams instead of multi-tasking on same team it will take less
than two days but more than a single day.

8.
Quantities & Workloads 8
This is just the tip of
the iceberg.
Microsoft Project as well as any other software
that cannot account for resource quantity will
get leveling of partial workloads wrong.
Microsoft Project
will incorrectly
report no
over-allocation
at all.
The increase from
1 day to 2 days is a
whooping 100%
increase in
duration!
That is too much to
be overlooked,
such wrong
resource leveling is
unacceptable.

9.
Quantities & Workloads 9
This is just the tip of
the iceberg.
If the duration of the activities is 20 days the software
calculation error would be 20 days!
The need for separate fields for resource quantity and effort is not
just a matter of convenience it is also a matter of getting reliable
resource overload visibility and resource leveling.